iOS 5 supports speedy Nitro JavaScript for full-screen Web apps

With the release of iOS 5 for the iPhone and iPad this fall, Apple will bring the Nitro JavaScript engine to full-screen Web applications saved to a user's home screen.

Currently, full-screen Web applications fail to use the Nitro acceleration Apple added to iOS 4.3. This can result in Web applications designed for the iPhone running much slower when saved to a home screen than they would if launched directly through the Mobile Safari browser.

But as highlighted on Thursday by CNet, the bug present in current version of iOS has been fixed in the first beta of iOS 5 delivered to developers. According to people familiar with the software, the Web.app feature in iOS 5 now has access to the Nitro JavaScript engine.

The fix was revealed by user "Xuzz" at Hacker News, who said that revealing the information was "probably" breaking their non-disclosure agreement with Apple. "Web.app now has the 'dynamic codesigning' entitlement, which enables Nitro," they said.

In a follow-up question, the user was asked about UIWebViews, which do not currently have Nitro benefits. "Xuzz" said that has not been added in iOS 5, but it's a security restriction.

"They can't give dynamic-codesigning to all apps, or their security (which taht disables, as a requirement to enable the JIT) would then be useless," they said.

SunSpider benchmark tests conducted earlier this year found that the Safari browser on the iPhone would run through code in 4.2 seconds. But a full-screen Web application saved to an iOS home screen would take more than twice as long — 10.2 seconds — to complete.

That's because full-screen Web applications, and native applications using UIWebView, use a different engine from Safari — an internal process called WebSheet.app.

The Nitro engine was first introduced in desktops in June of 2009 with the release of the Safari 4 Web browser. At the time, Apple boasted that Nitro could run JavaScript up to 4.5 times faster than its predecessor.

iOS 4.3 was released in March with the Nitro engine ported from the desktop, and making JavaScript performance twice as fast as it was in iOS 4.2.

Ooh. What's the alternative? I realize how old vBulletin is, but it's so prevalent and does so much that I've always thought it was still pretty much the best.

I don't know much about server-end stuff, so I don't really know what differentiates forum clients.

If there's going to be a switchover, we should have lists of options available so users can help decide (and make pros/cons charts and all that fun jazz).

Oh, right, iOS 5's Nitro. That's... great. OH, wow, I just remembered that I updated today. It was syncing (in the background... and while the screen was off. YAY!), so because of the parenthesized, I didn't remember that it was doing it. Guess I'll check stuff out.

This is cool and all, but I'd like to see web apps open in something that's not Safari. I don't use web apps b/c I'll often get up to all 8 Safari tabs going. I open a web app and boom, lose a page I meant to go back to and read later. Forever.

I also wish that when you open more than 8 tabs that the one that gets replaced would at least be able to use the back button to get back to the previous URL. That'd be like Christmas.

The 8 tab limit is fine, I just want to be able to hit back when I accidentally go over and lose one.

Ooh. What's the alternative? I realize how old vBulletin is, but it's so prevalent and does so much that I've always thought it was still pretty much the best.

I don't know much about server-end stuff, so I don't really know what differentiates forum clients.

If there's going to be a switchover, we should have lists of options available so users can help decide (and make pros/cons charts and all that fun jazz).

It was a hypothetical comment, I don't think there is any talk of a changeover to anything. There is other forum software, though UBB is one, I know I've used a forum that ran on the old UBB, there is apparently a new UBB that I haven't actually seen in use. vB might well be the best, but still, it's still pretty clumsy, especially on the admin side. Seems like there's an opportunity for someone to make a new product from scratch.